An electrostatic chuck includes a base having a support surface configured to retain a retaining target by electrostatic retention, and a thermocouple configured to detect a temperature of the base. The thermocouple includes first and second metal parts provided inside the base and having ends connected to each other to form a measuring junction, a first wire part having one end connected to the other end of the first metal part inside the base, and another end extending outside the base, and a second wire part having one end connected to the other end of the second metal part inside the base, and another end extending outside the base. The first metal part and the first wire part are formed from a first material, and the second metal part and the second wire part are formed from a second material different from the first material.
Legal claims defining the scope of protection, as filed with the USPTO.
1. An electrostatic chuck comprising: a base having a support surface configured to retain a retaining target by electrostatic retention; and a thermocouple configured to detect a temperature of the base, wherein the thermocouple includes a first metal part and a second metal part that are provided inside the base, wherein one end of the first metal part and one end of the second metal part are connected to each other to form a measuring junction, a first wire part having one end connected to the other end of the first metal part inside the base, and another end extending outside the base, and a second wire part having one end connected to the other end of the second metal part inside the base, and another end extending outside the base, wherein the first metal part and the first wire part are formed from a first material, and wherein the second metal part and the second wire part are formed from a second material different from the first material.
2. The electrostatic chuck as claimed in claim 1 , wherein the first metal part and the second metal part are covered by the base.
3. The electrostatic chuck as claimed in claim 1 , wherein the first metal part includes a first horizontal portion, extending in a direction parallel to the support surface, and having the measuring junction provided on one end of the first horizontal portion, and a first vertical portion, extending in a direction perpendicular to the support surface from the other end of the first horizontal portion, and having one end of the first vertical portion exposed from the base, and wherein the second metal part includes a second horizontal portion, extending in the direction parallel to the support surface, and having the measuring junction provided on one end of the second horizontal portion, and a second vertical portion, extending in the direction perpendicular to the support surface from the other end of the second horizontal portion, and having one end of the second vertical portion exposed from the base, wherein the one end of the first vertical portion is connected to the first wire part, and the one end of the second vertical portion is connected to the second wire part.
4. The electrostatic chuck as claimed in claim 3 , further comprising: an electrostatic electrode, embedded in the base, and configured to generate a Coulomb force between the base and the retaining target when applied with a voltage; and a heater element, embedded in the base, and configured to generate heat when applied with a voltage, wherein the first horizontal portion and the second horizontal portion are arranged at positions different from positions of the electrostatic electrode and the heater element along a thickness direction of the base.
5. The electrostatic chuck as claimed in claim 1 , wherein the first material and the second material are conductive materials having a melting point higher than a firing temperature of the base.
6. A substrate fixing apparatus comprising: a base plate having a first surface, a second surface opposite to the first surface, a first through-hole, and a second through-hole; and an electrostatic chuck according to claim 1 , mounted on the first surface of the base plate, wherein the first wire part is inserted into the first through-hole, and the other end of the first wire part is exposed from the second surface of the base plate, and wherein the second wire part is inserted into the second through-hole, and the other end of the second wire part is exposed from the second surface of the base plate.
7. The substrate fixing apparatus as claimed in claim 6 , wherein the first metal part and the second metal part of the electrostatic chuck are covered by the base.
8. The substrate fixing apparatus as claimed in claim 6 , wherein the first metal part of the electrostatic chuck includes a first horizontal portion, extending in a direction parallel to the support surface, and having the measuring junction provided on one end of the first horizontal portion, and a first vertical portion, extending in a direction perpendicular to the support surface from the other end of the first horizontal portion, and having one end of the first vertical portion exposed from the base, and wherein the second metal part of the electrostatic chuck includes a second horizontal portion, extending in the direction parallel to the support surface, and having the measuring junction provided on one end of the second horizontal portion, and a second vertical portion, extending in the direction perpendicular to the support surface from the other end of the second horizontal portion, and having one end of the second vertical portion exposed from the base, wherein the one end of the first vertical portion is connected to the first wire part, and the one end of the second vertical portion is connected to the second wire part.
9. The substrate fixing apparatus as claimed in claim 8 , wherein the electrostatic chuck further includes an electrostatic electrode, embedded in the base, and configured to generate a Coulomb force between the base and the retaining target when applied with a voltage, and a heater element, embedded in the base, and configured to generate heat when applied with a voltage, wherein the first horizontal portion and the second horizontal portion are arranged at positions different from positions of the electrostatic electrode and the heater element along a thickness direction of the base.
10. The substrate fixing apparatus as claimed in claim 6 , wherein the first material and the second material of the electrostatic chuck are conductive materials having a melting point higher than a firing temperature of the base.
11. A substrate fixing apparatus comprising: a base plate having a first surface, a second surface opposite to the first surface, a first through-hole, and a second through-hole; an electrostatic chuck according to claim 1 , mounted on the first surface of the base plate; and a controller configured to compute the temperature of the base based on a thermal electromotive force obtained from the thermocouple, wherein the first wire part is inserted into the first through-hole, and the other end of the first wire part is electrically connected to the controller, and wherein the second wire part is inserted into the second through-hole, and the other end of the second wire part is electrically connected to the controller.
12. The substrate fixing apparatus as claimed in claim 11 , wherein the first metal part and the second metal part of the electrostatic chuck are covered by the base.
13. The substrate fixing apparatus as claimed in claim 11 , wherein the first metal part of the electrostatic chuck includes a first horizontal portion, extending in a direction parallel to the support surface, and having the measuring junction provided on one end of the first horizontal portion, and a first vertical portion, extending in a direction perpendicular to the support surface from the other end of the first horizontal portion, and having one end of the first vertical portion exposed from the base, and wherein the second metal part of the electrostatic chuck includes a second horizontal portion, extending in the direction parallel to the support surface, and having the measuring junction provided on one end of the second horizontal portion, and a second vertical portion, extending in the direction perpendicular to the support surface from the other end of the second horizontal portion, and having one end of the second vertical portion exposed from the base, wherein the one end of the first vertical portion is connected to the first wire part, and the one end of the second vertical portion is connected to the second wire part.
14. The substrate fixing apparatus as claimed in claim 13 , wherein the electrostatic chuck further includes an electrostatic electrode, embedded in the base, and configured to generate a Coulomb force between the base and the retaining target when applied with a voltage, and a heater element, embedded in the base, and configured to generate heat when applied with a voltage, wherein the first horizontal portion and the second horizontal portion are arranged at positions different from positions of the electrostatic electrode and the heater element along a thickness direction of the base.
15. The substrate fixing apparatus as claimed in claim 11 , wherein the first material and the second material of the electrostatic chuck are conductive materials having a melting point higher than a firing temperature of the base.
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June 7, 2019
March 23, 2021
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